Is Pollution Turning Carnivorous Plants Into Vegetarians?

Gizmodo points us to an interesting post at Chem.info about a study that indicates that the increased levels of nitrogen in the air due to the burning of fossil fuels is dramatically altering the behavior of some carnivorous plants.

Studying sundews growing in Swedish bogs, researchers at Loughborough University found the plants growing in heavily polluted areas were only getting 22 percent of their nitrogen from trapping and consuming insects like they evolved to. Instead, these carnivorous plants were being supplied with nitrogen that was deposited in the bogs from polluted rain. While 57 percent of sundews in areas with light pollution were still trapping insects for their nitrogen needs.

Is this evolution or an example of the affects of man-made pollution?

By analyzing the presence of various isotopes of nitrogen in the plant samples researchers were able to pinpoint which plants were getting nitrogen from their roots, and which were getting it from insects. While this is good news for bugs it could potentially spell doom for the species.

“In the sites with more nitrogen deposition, these plants now get much more of their nitrogen from their roots, but they still have to bear the residual costs of being carnivorous, and other plants without these will be better able to survive,” explains lead researcher Jonathan Millet. “So it’s quite likely we’ll see less abundance and perhaps local extinctions from carnivorous species. The individual plants get bigger and fitter, but the species as a whole is less well adapted to high-nitrogen environments and will lose out over time.”

They also observed that sundews in polluted area were producing less sticky leaves with which to trap insects and were less colorful than their counterparts in cleaner areas. If you have ever grown sundews you know the bright coloring and sticky leaves is what help the plant attract and trap insects.